\documentclass{article}
\usepackage{tikz,amsmath}
\usetikzlibrary{arrows.meta, intersections}
\usepackage[graphics,tightpage,active]{preview}
\PreviewEnvironment{tikzpicture}
\begin{document}
\begin{tikzpicture}[>=Stealth, scale=0.8]
    \draw [->, name path=x] (-2, 0) -- (3, 0) node[anchor=west] {$x$};
    \draw [->] (0, -1.5) -- (0, 3) node[anchor=east] {$y$};
    \node [font=\footnotesize, fill=white, inner sep=0pt] at (0.3, -0.3) {$O$};

    \draw[name path=curl,domain=-1.1:1.6,smooth,samples=50] plot (\x, {2*\x*\x - \x - 1});
    \fill [name intersections={of=x and curl}]
        (intersection-1) circle (2pt) node[above left] {$x_1$}
        (intersection-2) circle (2pt) node[above right] {$x_2$};
\end{tikzpicture}
\end{document}
